Whether you're sitting in the middle of
the Mojave Desert or three days out of
New Orleans bound for Aberdeen...
...here are some thoughts on fuel systems
that could mean a lot to you
Smooth operation of your fuel sys-
tem is as critical as any function on
your ship. And when you're a thou-
sand miles out of port, you are just
as vulnerable as the fellow whose
power plant sits
in the middle of
the desert —
there's just no
way any equip-
ment manufac-
turer's service
crew is going to
reach you as
quickly as you
need when you're in trouble. When
difficulties arise the only resources
you have to rely on are your own.
If you're lucky, the people who
built your power plant thought about
this long before-
hand and speci-
fied major com-
ponents of high
reliability and
maintainability.
They understood
that the idea of
preventive main-
tenance actually
extends back to the equipment man-
ufacturer and starts long before a
plant or ship is ever commissioned.
Ask anyone who ever served belowdecks
Marine engineers have known this
for a long time, which is why you
find IMO® pumps specified almost
exclusively for engine room and fire
room service in commercial vessels
and both surface and underwater
ships of the U.S. Navy. It's also why
you will find that most men in your
profession know that IMO pumps
are some of the most reliable pieces
of equipment you can find anywhere.
There are three basic reasons for
reliability—the first is design
The three screws of an IMO pump
are generated according to involute
geometry, a thread form so precise
that oil is moved
axially with high
volumetric effi-
ciency but with-
out significant
metal-to-metal
contact between
the screws. Nor
is there metal-
to-metal contact
between the
screws and their
housing. Ahydro-
dynamic oil film supports them in
their bores just like journals. Thus,
little friction and wear develop any-
where in an IMO pump. And because
there are no radial bending loads
and axial loads are balanced hy-
draulically, there is little that ever
goes wrong with it beyond an occa-
sional seal needing replacement.
The second reason is manufacturing
Rotors in IMO pumps from Delaval
are deep-nitrided to Rc 55/60. This
heat treatment is entirely different
from surface improvement tech-
niques which do not provide a case-
hardened surface. Rotors are then
thread-ground for maximum accu-
racy and to compensate for distor-
tion under load. Expedients like lap-
ping can't accomplish this and can
even introduce running interference.
As for the rotor housing bores,
Delaval expends as much care on
them as on the rotors. All three bores
are broached simultaneously to give
consistently accurate clearance and
optimum surface. What these fea-
tures all add up to is greater pres-
sure capability, greater margin when
handling low viscosity fuels or run-
ning at elevated temperatures, and
most of all, less wear, longer life,
fewer troubles.
A third reason is maintainability
All Delaval IMO pumps recom-
mended for fuel service incorporate
replacement rotor housings within a
permanent case. If you ever do have
trouble with a pump, you don't have
to throw out the baby with the bath
water. You can do repairs quickly
without renewing external casing.
(The separate housing within the cas-
ing is also an extra safety feature.)
When you are at sea, knowing that
fuel in your power plant is moved by
IMO pumps gives a man a secure
feeling. It's good to know, too, that
when you're in port, a local Delaval
representative is only as far as your
telephone. Call him whenever you
want information about any aspect
of specifying, using or
maintaining Delaval
IMO fuel pumps. Or if
you want, write di-
rectly to IMO Pump Di-
vision, Delaval Turbine
Inc., POB 321, Tren-
ton, NJ 08602, or call
609: 587-5000.
For 46 years Delaval has been
making IMO pumps for practically
every marine fuel: Bunker C, NSFO,
Navy distillate, crude, JP-5, resid-
uals and blends. Delaval IMO pumps
have been proven in steam plant
burner and transfer service, gas tur-
bine fuel injection, and diesel
engine fuel service. That's a long,
long record of reliability.
DEL 352A
October 1, 1978 5
ATransamerica Company
Digital Wave Publishing